Electromagnetic wave controlling apparatus



May 12, 1953 1'. J. KEARY ELECTROMAGNETIC WAVE CONTROLLING APPARATUS Filed Sept. 18, 1945 INVENTOR THOMAS JOSEPH KEARY E FW P n A.

Patented Ma 12, 1953 2,638,547

iE EG -B M G ET' C V QQ T-RQLL N WA Thomas J asap}; Keggy, Broc lgtox l, Mass agsignpg',

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Forward of the transverse dipole I9 substantially a quarter wave length there is positioned a reflector dipole 24 for the purpose of preventing direct forward radiation from the dipole l9 and thereby avoiding an unnecessarily wide beam. This may be supported by an insulating mounting (not shown) or by extending the line 5 so as to form a quarter wave stub (not illustrated) to provide support both for the inner conductor 9 and the reflector dipole 24. In this case the dipole 24 would be secured to the outer conductor l3 while the inner conductor 9 would be supported by a shorting plate closing the end of the quarter wave stub that is adjacent dipole 24. One arm of the dipole I9 would be connected to the outer conductor l3, and the other arm would be connected to the inner conductor 9 and extend through a suitable aperture in the outer conductor 53. The application of Wright above mentioned may be referred to for further details of such a reflector and support.

To divide properly between the transverse dipole l9 and the axial dipole 2|, 22 the energy from a coaxial feed line 26 with an inner conductor 21 and an outer conductor 28, a variable power dividing device is needed so that the offsetting effect may be produced. By varying the division of power the degree of offset may be varied and hence a transverse scanning will be produced. The relative lengths of lines 5 and l from the power divider are adapted to provide the proper phase difference between the excitation of the respective dipoles so that a beam deviation will result. The amount of deviation is then controlled by the relative intensity excitation of the respective dipoles l9 and 2l22, the transverse dipole IQ however having at all times the much greater share of the energy.

One device for variably dividing the power is shown in the figure, including a section of coaxial transmission line with inner conductor 30 and outer conductor 32 connected to the power input I line 26 at a junction designated by numeral 34 and also connected to dipole feed line 5 atpoint designated by numeral 36 and to dipole feed line '1 at point designated by numeral 38. A complete description of this type of variable power divider may be found in patent application of George L. Ragan entitled Power Divider Circuit Serial No. 592,798, filed May 9, 1945, now Patent 2,605,356, issued July 29, 1952. In brief, the apportionment of power by the device results from r the fact that ,adjustably positioned short circuiting plungers 4i) and 42 are provided so that there results a short circuited stub in parallel with each of the respective lines 5 and I which feed the two dipole antenna elements l9 and 2l22. If the two outputs are matched for one setting of the plungers and if also the plungers are mechanically ganged so that the length of one stub is greater than the other at all times by one quarter of a wave length then the input 28 will be continuously matched for all positions of the plungers. Moreover there results a division of power between the two outputs into lines 5 and 1 respectively proportional to the conductances of the respective stubs, while the reactive components introduced by the stubs will cancel at all positions. A suitable frame or yoke and driving mechanism (not shown) may be attached to tubes 44 and 45 to cause the plunger-s 40 and 42 to move back and forth and thus produce a periodic variation in the power fed to the dipoles l9 and 2l22 respectively. This in turn will cause the radiation beam from the reflector I to swing back and forth transversely at the same rate through a small angle. 7

Deviation of the beam may also be accomplished by varying the relative phasing between the traverse dipole and the axial dipole by variably inserting dielectric material in the feed line to one of the dipoles or by otherwise periodically varying the electrical length of one of the feed lines in any of several conventional ways (not shown).

What I desire to claim and secure by Letters Patent is:

1. A directional antenna system for transverse scanning over a narrow angle, comprising a paraboloidal reflector, a dipole positioned near the focus of said reflector and substantially perpendicular to the direction of the axis thereof, a dipole positioned near the focus of said reflector and substantially parallel to the axis, means for variably apportioning high frequency electrical energy to the said dipoles, and a reflector dipole disposed in spaced relationship to and occupying a position more remote from said paraboloidal reflector than said first named dipole.

2. A directional antenna system for producing a narrow radiation beam which may be caused to scan back and forth through a narrow angle, comprising a paraboloidal reflector, a dipole positioned near the focus of said reflector and substantially perpendicular to the direction of the axis of said reflector, means for variably energizing said dipole with high frequency electric energy, an auxiliary reflector occupying a position more remote from said paraboloidal reflector than said dipole, a dipole positioned near the focus of said paraboloidal reflector and substantially parallel to the direction of said axis, and means of variably energizing said last-named dipole with a relatively smaller amount of said energy.

,3. A directional scanning antenna system comprising, a paraboloidal reflector, a dipole positioned near the focus of said reflector and substantially perpendicular to the direction of the axis of said reflector, means for energizing said dipole with high frequency electrical energy, an

.auxiliary reflector occupying a position more reto the direction of said axis, and means for energizing said last named dipole with high frequency electrical energy of variable phase relative to the phase of said first mentioned energy.

4. A directional scanning antenna system comprising a paraboloidal reflector, two dipoles positioned near the focus of said reflecto one substantially paralle1 to and one substantially perpendicular to the axis of said reflector, two coaxial transmission lines for energizing said dipoles, an auxiliary section of coaxial transmission line, an input transmission line for energizing said auxiliary line, said auxiliary line seeton having connections respectively with said two coaxial lines on opposite sides of the connection to said input line, two short circuiting plungers inserted in said auxiliary section beyond said connections respectively such that the distance from one plunger to the one of said connections nearer to it exceeds by one quarter of an electrical Wave length the distance from the other plunger to the other of said connections, means for causing said plungers to move in unison so as to vary periodically the said distances by equal amounts, and an auxiliary reflector occupying a position more remote from said paraboloidal reflector than said second named dipole.

5. A directional antenna system comprising a paraboloidal reflector, a first dipole positioned near the focus of said reflector and substantially perpendicular to the axis thereof, a second dipole positioned near the focus of said reflector and substantially parallel to the axis of said reflector, a reflector dipole disposed in spaced relationship to and occupying a position more remote from said paraboloidal reflector than said first dipole and means for supplying high frequency energy to said first and second dipoles.

6. A directional antenna scanning system comprising a paraboloidal reflector, first and second antenna elements disposed substantially at the focus of said reflector, one of said antenna elements being oriented parallel to and the other perpendicular to the axis of said reflector, first and second transmission lines extending through said reflector for respectively energizing said first and second antenna elements, an auxiliary section of transmission line coupling said first and second transmission lines, an input transmission line coupled to said auxiliary line section, a pair of mechanically coupled line terminating elements in said auxiliary line section, and means for oscillating said terminating elements in uni- $011.

7. An antenna having variable directivity comprising, a paraboloidal reflector having a finite focus, first and second closely adjacent feed lines projecting through said reflector near the vertex thereof and terminated substantially at the focus of said reflector, first and second antenna elements supported at the termination of said first and second feed line, respectively, one of said antenna elements being oriented parallel to and the other perpendicular to the axis of said reflector, and means coupled to said feed lines for variably apportioning high frequency energy to said antenna elements.

8. An antenna having variable directivity comprising, a paraboloidal reflector, first and second radiating dipoles each positioned substantially at the focus of said reflector, one of said dipoles being oriented parallel to and the other perpendicular to the axis of said reflector, separate feed lines for said first and second dipoles, and means coupled to said feed lines for variably apportioning high frequency energy to said dipoles.

9. An antenna having variable directivity comprising, a paraboloidal reflector, first and second radiating dipoles positioned near the focus of said reflector, one of said dipoles being oriented parallel to and the other perpendicular to the axis of said reflector, and means coupled to said dipoles for variably apportioning high frequency energy to said first and second dipoles.

10. An antenna having variable directivity comprising, a paraboloidal reflector, first and second radiating antenna elements positioned near the focus of said reflector, one of said elements being oriented parallel to and the other perpendicular to the axis of said reflector, and means coupled to each of said elements for variably apportioning high frequency energy thereto.

THOMAS JOSEPH KEARY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,054,896 Dallenbach Sept. 22, 1936 2,380,981 McElhannon Aug. 7, 1945 2,412,867 Briggs et a1. Dec. 1'7, 1946 2,430,568 'I-Iershberger Nov. 11, 1947 2,465,673 Breen Mar. 29, 1949 

